The number of devices which have recently been developed for use in connection with various catheters and which are specifically intended to prevent accidents from occurring upon removal of the needles employed therewith has grown dramatically. This has primarily been the result of concern among nurses and other medical personnel for the onset of infectious diseases, including the problem of AIDS, which has resulted from the handling of needles, catheters, cannulas and the like. Thus, the disease of AIDS and other such infectious diseases have been known to occur upon accidental pricking of such personnel from such needles after they have been removed from patients.
Reference to catheters throughout this application is intended to relate to the large number of variations of needle-containing devices of this type. These not only include intravenous catheters, which include a combination of elements for passing fluid to or from a fluid-carrying conduit or blood vessel in a patient, as well as angiocath-type devices, which employ a needle for the implantation of a plastic cannula or the like which can remain within the patient even after removal of the steel or other metallic needle used therewith.
Thus, in the case of the various intravenous-type catheters, a tubular conduit is generally employed with a connector at one end in order to connect the tubular conduit into a source of enteral fluid for delivery to the patient or to a reservoir for receiving fluid from the patient, and a second connector at the opposite end from the first connector which is fixedly or removably connectable to the needle.
On the other hand, in the case of angiocath-type devices, these can include a chamber for the removal of a small amount of bodily fluid or blood upon implantation, primarily to determine that the device is in proper working order and that the plastic cannula has been properly implanted, but which is then removed along with the needle so that the plastic cannula can serve various purposes, including subsequent use for the removal or insertion of fluids, etc.
In each of these cases, the problems of exposure to the needles, whether they are used solely for implantation of plastic cannulae or for intravenous applications themselves, have been considerable.
A recent significant advance in this field is represented by U.S. Pat. No. 4,966,589 and pending U.S. application Ser. No. 07/522,382 filed on May 11, 1990, to the present applicant, in which composite catheter assemblies are disclosed for this purpose. These include an embodiment in which, after removal, the needle can be readily withdrawn into a closed chamber so that it is no longer exposed and no longer presents a danger to medical personnel. In the devices shown in the '589 patent, retraction of a contaminated needle into the barrel is effected by depressing manual button 42 to release ratchet 36 and thus permit spring 28 to expand and move the carrier 26 to its retracted position within chamber 19.
While this device has thus provided a rather significant improvement in this field, the search has continued for additional improvements, and, in particular, for such protective catheter devices which include extension and retraction mechanisms with fixed positions for controlling the various placements of the needle itself within and without these devices.